The typical method of supplying low voltage lamps, halogen in particular, from a high voltage supply (e.g., 120 volt, 60 Hz) is to use conventional half-bridge, high frequency inverters. These use a level shifting scheme to periodically switch on and off the high side switch. One design would be to employ a step-down transformer between the supply voltage and the low voltage lamp. Several disadvantages of this method are that transformers operating at 60 Hz are typically larger and heavier than would be needed at higher frequencies, step-down transformers are relatively expensive, and there is no inherent short circuit protection when employing a step-down transformer.
The present invention provides a ballast circuit for halogen, or other low voltage lamps, that overcomes the foregoing drawbacks.